Re: [Haskell-cafe] Propositional logic implementation

I like using smart constructors to replace :<=>: and :=>: a \/ b = a :\/: b a /\ b = a :/\: b a ==> b = Not a \/ b a <=> b = (a ==> b) /\ (b ==> a) Also, if you generalize Sentence a bit you get a really nice formulation of "true". See my paste at http://hpaste.org/13807#a2 -- ryan 2009/1/10 Andrew Wagner :

Nice Idea, though I don't know that I want something that extensive. I was more looking for whether there was a better way I could define the algebraic data type.

On Sat, Jan 10, 2009 at 6:04 PM, Miguel Mitrofanov wrote:

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Look at SYB (Data.Data, Data.Generics.*). For example, your "symbols" function can be rewritten as

symbols :: Sentence -> [Symbol] symbols s = nub $ listify (const True) s

"true" is not that simple, because this code is NOT boilerplate - each alternative is valuable by itself.

On 10 Jan 2009, at 23:56, Andrew Wagner wrote:

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All, Is there some better way to do this? It seems like a lot of boilerplate. Thanks!

http://hpaste.org/13807#a1 _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

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